Scientists from Wake Forest University in North Carolina aroused the world's interest by successfully performing the world's first replacement of erectile tissue of the penis. And yes, it's somewhat fitting that they chose the rabbit to perform the Frankenweenie experiment:

In a previous study, the researchers engineered short segments of rabbit erectile tissue with 50% of full function.

In the latest work, they harvested smooth muscle cells and endothelial cells from the animals' erectile tissue.

These cells were multiplied in the laboratory and used to seed a three dimensional scaffold, which was implanted into the animals' penis.

Organised erectile tissue with blood vessel structures began to form as early as a month later.

The researchers believe the key was the fact that the cells were injected into the scaffolds on two separate days, enabling them to hold almost six times as many smooth muscle cells as in previous studies.